diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 9871e649ffeffe8798cd20a1450377a4f4777fca..8c5a956f3d9c259ddead3d5414548500d6d53624 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1754,7 +1754,7 @@
 			Format: { "0" | "1" }
 			0 - Use IOMMU translation for DMA.
 			1 - Bypass the IOMMU for DMA.
-			unset - Use IOMMU translation for DMA.
+			unset - Use value of CONFIG_IOMMU_DEFAULT_PASSTHROUGH.
 
 	io7=		[HW] IO7 for Marvel based alpha systems
 			See comment before marvel_specify_io7 in